中文摘要：

采用超音速等离子喷涂技术在45号钢基体上预制Ni60合金涂层,利用定向冷却装置在不同流量冷却水条件下,对感应重熔后的涂层进行强制冷却。通过OM、SEM（EDS）、XRD等手段研究了不同流量冷却水对感应重熔涂层组织结构的影响。结果表明：随着冷却水流量的不断增大,感应重熔涂层的组织结构发生了极大改变,涂层与基体之间形成了一条明显的冶金结合带;当流量为80 L/h时,涂层中形成的＂十字架＂形结构的定向凝固组织结构致密细小,对称性最好,且具有较好的取向一致性;晶粒沿[001]方向的偏离角θ较小,仅在0°~8°之间,而具有高度（（200）晶面）择优取向趋势。

英文摘要：

The Ni60 alloy coating was prefabricated on 45 steel substrate by supersonic plasma spraying technology and fasted cooling was then conducted on the coating by directional cooling device under conditions of cooling water at different flux after induction remelting. The effect of cooling rate on the microstructures of the induction remelting coating was investigated by OM, SEM （EDS） and XRD, etc. The results indicate that the microstructures of the coating change greatly and the metallurgical bond forms between the coating and substrate with the increase of flux of the cooling water. When the flux of cooling water is 80 L/h, the directional solidification microstructures of the cross in the coating are dense and fine. The symmetry of the cross is perfect and the orientation of the cross is well consistent. Besides, its deviation angle is small with respect to the [001] direction and the range of deviation angle is 0°-8°. At the same time, it has a highly preferred orientation along the （200） crystallographic plane.